Please consider a MongoDB collection with the following document:
"_id": "clientsInfo"
"data": {
"clientsList" : [
{
"name" : "Mike",
"country" : "USA"
},
...
]
}
After setting the DataSet and defining the Query like this...
{
collectionName:'projectA',
findQuery: {
'_id':'clientsInfo',
},
findFields: {
'_id':0,
'data.clientsList':1
},
}
...I am able to display the first item of the fetched array (`java.util.List` type) in JasperSoft Studio inside a Text Field using the following expression:
But, considering that I would like to exhibit the whole data in a Name/Country Table...
Question1: How could I access any of the dictionary fields? Trying [get method][1] I obtain The method get(String) is undefined for the type Object. error. However, knowing that the object is an instance of com.mongodb.BasicDBObject it should have that method inherited (See [doc][2]).
I have also tried to cast object to org.json.JSONObject but then I get net.sf.jasperreports.engine.fill.JRExpressionEvalException: Error evaluating expression for source text: (JSONObject)$F{data.clientsList}.get(0) error.
Question2: Let's suppose we have already solved first question... How can I iterate the list to access not only the first item but all of them according to the array length? Is it possible to use for-loop sentence inside the JasperSoft Expression Editor? ([if-then-else seems to be available][3])
Thanks in advance, Any clue that point me in the right direction will be appreciated.
Note: If someone wants to earn StackOverflow reputation, question is also placed there: http://stackoverflow.com/questions/41396004/which-is-the-proper-way-to-w...
1 Answer:
Posted on January 25, 2017 at 1:16am
Just in case someone was in the same situation as I was, I must say this whole approach was wrong.
It's not about making a simple query which returns big block of complex data formatted as an object or list of objects and then manipulate it with JasperSoft Studio. Instead, what I had to do was design a more elaborated query which returns the simple fields I wanted to use straightforward. How to do this? By using Aggregation Framework.
So, by changing this...
{
collectionName:'projectA',
findQuery: {
'_id':'clientsInfo',
},
findFields: {
'_id':0,
'data.clientsList':1
},
}
...for this...
{
runCommand: {
aggregate : 'projectA',
pipeline : [
{'$match': {'_id':'clientsInfo'}},
{'$project': {'data.clientsList': 1}},
{'$unwind': '$data'},
{'$unwind': '$data.clientsList'}
]
}
}
...is how I get `name` and `country` fields in order to use them in Text Fields, Tables, ...etc.
